generate_preliminary_analysis: Generate preliminary analysis report
In joebrew/maragra: An analysis of malaria at the Maragra sugar company, Mozambique

Generate an html report of the preliminary analysis report, originally prepared in August / September 2017

generate_preliminary_analysis(
  date = NULL,
  output_dir = NULL,
  output_file = "maragra_preliminary_analysis.html"
)

`date`	A date to be printed on the report. If `NULL` (the default), the current date will be used
`output_dir`	The directory to which the file should be written. If `NULL` (the default), the current working directory will be used.
`output_file`	The name of the file to be written.